1. Field of the Invention
The present invention relates to a drive control device for an electric vehicle such as a hybrid automobile or an electric automobile or the like, and to an electric vehicle equipped with such a drive control device.
2. Description of Related Art
With a gasoline engine, the drive force needed under various types of driving conditions is obtained by using a transmission, since the torque at low speed is low and the rotational speed region possible for driving is narrow. On the other hand, with an electric motor, it is possible to obtain the necessary drive force without using any transmission, since the torque at low speed is high and the rotational speed region possible for driving is broad. Accordingly, with a typical electric automobile, no transmission is provided, and the output shaft of the electric motor is connected to the drive wheels directly or via a final reduction gear and a differential gear device.
Since with an electric automobile, as compared to a gasoline engined vehicle, it is possible to control the torque at high accuracy and moreover at high speed, accordingly such an automobile never operates in an idling state, as is the case with a gasoline engined vehicle. In other words the driving feeling is different from that of a gasoline engined vehicle, since during deceleration engine braking due to the rotation of the engine is not generated. With the invention disclosed in Japanese Laid-Open Patent Publication 2009-44871, at low speed the torque of an electric motor is controlled so as to generate creep torque simulating the creep torque that is present during operation of a gasoline engined vehicle equipped with an automatic transmission, while at medium and high speed regenerative braking is performed by utilizing the electric motor as a generator, so that braking force is generated corresponding to engine braking. By doing this, while obtaining braking force, it is also possible to recuperate to the battery the electrical power that is generated.